What is a PDB file?

A PDB file contains information for the debugger to work with. There's less information in a Release build than in a Debug build anyway. But if you want it to not be generated at all, go to your project's Build properties, select the Release configuration, click on "Advanced..." and under "Debug Info" pick "None".

I had originally asked myself the question "Do I need a PDB file deployed to my customer's machine?", and after reading this post, decided to exclude the file.

Everything worked fine, until today, when I was trying to figure out why a message box containing an Exception.StackTrace was missing the file and line number information - necessary for troubleshooting the exception. I re-read this post and found the key nugget of information: that although the PDB is not necessary for the app to run, it is necessary for the file and line numbers to be present in the StackTrace string. I included the PDB file in the executable folder and now all is fine.